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Corresponding Author

Bing LIU(ice6377@tust.edu.cn);
Shuo WANG

Abstract

Aflatoxin B1 has attracted much attention because of its high toxicity and carcinogenicity, which has become a great concern in food safety. Based on the principle of specific binding between Aflatoxin B1 and its aptamer, an aptamer-based electrochemical sensor had been designed and developed for the determination of minor Aflatoxin B1 contained in grain. The mesoporous carbons were first modified on the surface of the working electrode, and then the gold nanoparticles were on-site electrodeposited at a constant potential. Each modified electrode was characteritised by scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). As a result, the surface area and the electrochemical signal of the modified electrode were all greatly increased, providing more attachment sites for the following conjugation of the aptamer. During the detecting process, Aflatoxin B1 could compete with methylene blue on the aptamer chain to cause methylene blue shedding and the electrochemical signals were changed which could be used to quantify the concentration of Aflatoxin B1. The surface modifications could evidently improve the conductivity and sensitivity of the sensor. A linear response in current to Aflatoxin B1 was found ranging from 0.1 to 75 μg·L-1 with the detection limit as low as 36 ng·L-1 (S/N = 3). The spiked recovery tests of different grains (rice, corn, glutinous rice) revealed that the recovery rates were between 92.3 and 103.6%, showing excellent accuracy, sensitive quantitative detection of the target substance and good reproducibility. This work has demonstrated a new method to develop a novel, simple, fast and sensitive sensor for the detection of trace amount of Aflatoxin B1 in grains.

Graphical Abstract

Keywords

Aflatoxin B1, aptamer, sensor, detection method

Publication Date

2020-06-28

Online Available Date

2019-06-07

Revised Date

2019-04-11

Received Date

2019-02-19

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